肠道微生物调控GLP-1R对精神分裂症伴代谢综合征的作用机制

Metabolic syndrome is a common adverse effect of antipsychotics, which severely affects the patients' compliance to treatment and increases significantly the risks of diabetes and cardiovascular diseases. However, the mechanism is still not clear. In our previous studies, we found that GLP-1 which modulates the pathway of insulin secretion is closely linked with schizophrenia-related metabolic disturbances. The transcriptomic study of gut bacteria revealed that GLP-1R, the receptor of GLP-1, is linked with gut bacteria and may induce obesity, insulin resistance and metabolic syndrome. But we still don't know clearly how gut bacteria take effect. In this study, the profile of gut bacteria will be compared between the schizophrenic patients with metabolic syndrome and those without metabolic syndrome using fecal microbiota sequencing. Combining the previous studies on metabolomics and miRNomics, the correlation of different bacteria with the amount of various metabolites and other clinical indices will be analyzed using the WGCNA network method based on bacterial abundance analysis. Hence, the key bacterial strains will be identified and be further independently verified. Next, the GLP-1R gene will be knocked out or overexpressed in the Caco-2 cell line co-cultured with the key gut bacteria. Using the Dual RNA-seq method and the real-time analysis of cellular energy metabolism, we hope to find out the possible mechanism of GLP-1R mediated metabolic changes and to explore that of metabolic syndrome in schizophrenia.

代谢综合征是抗精神病药物常见不良反应，严重影响患者治疗依从性，且显著增加糖尿病及心脑血管疾病的患病风险，目前发病机制尚不明确。课题组前期研究发现胰高血糖素样肽-1（GLP-1）调节胰岛素分泌通路与精神分裂症代谢异常相关，转录组测序数据显示其受体GLP-1R可能与肠道微生物、肥胖、胰岛素抵抗和代谢综合征相关，但其介导代谢异常的肠道微生物作用机制尚不清楚。本项目拟针对伴和不伴代谢综合征的两组精神分裂症患者，进行肠道微生物组测序，结合前期代谢组学和miRNA组学研究基础，基于菌种丰度构建WGCNA网络，探究菌种、代谢物和临床指标间的关联，锁定潜在的关键菌种并进行独立样本验证。进而针对Caco-2细胞敲减或过表达GLP-1R，与关联细菌共培养，利用Dual RNA-Seq，结合细胞能量代谢实时检测，找到与GLP-1R介导微生物可能的相关机制，为探索精神分裂症伴代谢综合征的机制提供新思路和理论依据。

抗精神病药物所致代谢紊乱在临床高发，降低了患者生存质量，且显著增加糖尿病及心脑血管疾病的患病风险，既往研究报道其可能与肠道微生物、生活方式、遗传背景等相关，但未明确相关病因机制。本研究共入组被试210人，其中抗精神病药物所致代谢综合征79人，抗精神病药物未致代谢综合征71人和健康受试者60人，开展肠道16SrRNA高通量测序和血浆非靶向代谢组学检测，以揭示抗精神病药物相关代谢综合征的特征肠道微生物和小分子物质。研究发现菌属Acinetobacter、Muribaculum等在抗精神病药物相关代谢综合征组丰度相对升高，Phocaeicola丰度在抗精神病药物不诱导代谢综合征组降低，而1−Monoolein，FAHFA(3:0/2−O−22:0)等物质在抗精神病药物不诱导代谢综合征组相对较多，这些菌属和代谢物既往报道与肥胖、糖尿病调控相关，后续需要实验进一步明确其与抗精神病药物相关代谢紊乱的关系并明确其参与的机制。此外，动物实验发现GLP-1及其受体具有潜在影响抗精神病药物诱导代谢综合征的中枢作用。通过饲料中添加奥氮平给药的方式，我们成功构建奥氮平所致小鼠体重增长及摄食异常模型，该模型小鼠表现出空腹血糖水平显著上升。此外，腹腔注射奥氮平可以迅速升高血糖并维持高血糖状态2个小时。基于以上模型，我们进一步通过免疫荧光技术结合超声功能成像技术，发现在奥氮平效应脑区之一外侧隔核脑区中，GLP-1受体表达活化的神经元数目显著下降。此外，外侧下丘脑也具有异常活化的GLP-1受体表达神经元，提示慢性给药模型中外侧隔核及下丘脑的GLP-1受体表达神经元可能参与奥氮平诱导肥胖及血糖异常表型的发生发展，阐明通过调节GLP-1受体及其相关神经环路可在奥氮平副作用发生中起到神经活性调控作用。